It happens that arteriosclerosis or the like cause stenosis in the blood vessel and that blood flow to the peripheral side can be hardly obtain or can not be obtained. In such cases, a bypass operation is practiced, to bypass the stenosis site of the patient's own artery, vein or an artificial blood vessel, and to anastomose the central side and the peripheral side of the vessel.
While practicing this blood vessel anastomosing, in order to obtain a good vision of the anastomotic site, in general, a method of pressing temporarily both ends of the vessel to be anastomosed and to decrease or stop the bleeding from the anostomotic site, was taken conventionally. On the other hand, in case the stenosis site is not completely closed, as blocking blood flow during blood vessel anastomosing may cause adverse effects to the peripheral side, therefore, a method wherein blood flow is secured even during the anastomosing operation is anticipated.
The present inventors have disclosed previously a blood vessel anastomosing auxiliary tool having circular projections (corresponding to the bulky portions of the present invention) on a hollow conduit, as described in Japanese Laid-Open Patent Application No. 11-335. Said auxiliary tool consists of a hollow conduit comprising circular projections (bulky portion) at the ends, and a filamentary retrieving means at the central part, having elasticity to self-restore the hollow conduit bent after it is inserted into a blood vessel.
The use of the above described anastomosing auxiliary tool, have permitted to practice blood vessel anastomosing without completely blocking the blood flow. However, said blood vessel anastomosing auxiliary tool is formed (disposed) so that the shaft center of the conduit (shaft center of the non-bulky portion) and the shaft center of circular cross section formed at the outer edge of the circular projection (corresponding to the bulky portion of the present invention) in the shaft direction of said conduit, are to be substantially the same. Therefore, when the bulky portion of said auxiliary tool is inserted into a blood vessel, as it is shown in FIG. 10, the space formed between the bulky portion and the inner wall of the artery blood vessel to which the tool is inserted, was small, and this was sometime an obstacle when anastomosing blood vessel. That is, when anastomosing blood vessel to another one, when the space was small as shown in FIG. 10, there was a disadvantage that the suture needle would touch the anastomosing auxiliary tool, which caused difficulty for anastomosing.
Furthermore, as for the anastomosing auxiliary tool described in Japanese Laid-Open Patent Application No. 11-335, there was a problem that it was difficult to insert the hollow conduit into a blood vessel. That is, at the time of the operation, it was not easy to insert the above hollow conduit directly into a blood vessel from the opening (incision) of the blood vessel. Therefore, it was necessary to ensure the opening (of the blood vessel) to make the insertion easy.
Moreover, there were several points to improve as for the towing means of the hollow conduit of the anastomosing auxiliary tool of this invention. That is, when retrieving the anastomosing auxiliary tool from the blood vessel after the anastomosis, it is necessary to hold the filamentary towing means and to pull it. However, as it is made from a fine string, it was sometimes difficult to hold it tightly or it happened to drop off the end of the string. Therefore, in order to hold the string or to confirm the end of the string or the like (or to fill out the necessary information), a tool wherein a small plate (tab) is attached on the other end of the string attached to the hollow conduit has also been devised. In this manner, by attaching a tab to the end of the string, it became easier to retrieve the hollow conduit from within the blood vessel. However, as the conventional tab was not designed to be held tightly, it was difficult to hold it tight, and it slipped when moving or pulling the tab with forceps, and it took time to retrieve the hollow conduit (the anastomosing auxiliary tool) from within the blood vessel.
The object of the present invention is to provide a blood vessel anastomosing auxiliary tool that has improved each of the above mentioned problems.